Project Summary: Urinary Stone Disease (USD) is an increasingly prevalent and highly recurrent condition associated with major morbidity at a rising cost to society. Thus, improved management can significantly reduce its health burden. Increasing fluid intake is recommended to all USD patients. However, knowledge gaps persist regarding the impact of fluid therapy in preventing USD recurrence including the optimal urine volume, safety of fluid therapy, effectiveness of strategies to achieve and maintain a high urine volume, and whether such strategies reduce USD recurrence. Although ureteral stenting is routinely performed after urological procedures for USD to mitigate peri-operative complications, stents cause significant patient discomfort. The causal mechanisms are only partly understood, and use of new stent biomaterial and medications post-stenting only partly relieve these symptoms. Limiting inflammation is one pathway to reduce stent-related discomfort. Based on current knowledge, we submit the following hypotheses: 1. Compared to standard practice, a strategy achieving a higher urine volume by combining counseling, frequent reminders, and fluid intake modification by feedback, safely reduces USD recurrence. 2. Biological factors identify USD patients likely to develop stent-related symptoms, and oral glucocorticoids reduce stent-related discomfort by mitigating inflammation. To test these hypotheses, we will pursue the following objectives in a multi-center collaborative effort: Aim 1. We will compare USD progression in patients randomized to standard care vs. achievement of a urine volume >2.5 L/day in adult and >30 ml/Kg/day in pediatric USD patients. We will also assess the impact of a customized strategy [combining counseling, frequent reminders (via mobile technology), and modification of fluid intake habits using feedback (from periodic assessment of urine volume surrogates)] on preventing USD recurrence. Aim 2. We will evaluate USD patients undergoing ureteral stent insertion at the time of unilateral ureteroscopy for USD and receiving standard-of-care medications with pre-, and post-procedural psychometric testing to identify predictors of greater stent-related symptoms. Based on the findings, we will randomize high risk patients to a 5-day methylprednisolone course or matching placebo to determine whether methylprednisolone as an adjunctive therapy safely reduces stent- related symptoms. Aim 3. We will collect blood, urine, DNA and stool from stone formers as a resource for USD Research Network investigators and other researchers. To achieve these aims, this application will combine the expertise of established USD researchers and clinicians with a large base of USD patients to participate in a collaborative effort with other USD investigators with the ultimate aim of improving USD patient care.